Piston pumps for delivering pressure media in hydraulic brake systems with ABS and/or ESP functionality (ABS: antilock braking system, ESP: electronic stability program) are known from the prior art in various embodiments. For example, in vehicle brake systems, often radial piston pumps are used with a plurality of pump elements for delivering pressure media, in which at least one piston can be moved to and fro by means of an eccentric. Typically, these so-called pump elements consist of a piston, a piston running face normally formed as a cylinder, inlet and outlet valves, and sealing elements. The valves serve to control the fluid on the pumping movement of the piston. The inlet valve here serves to prevent the fluid from flowing back into the intake chamber during the compression phase, the outlet valve prevents the fluid from flowing back from the pressure side into the pump interior. Also, downstream of the outlet valve of the piston pump, a choke device is provided with a static and a dynamic choke point which open and close depending on the flow quantity or the resulting flow differences. The static choke point brings advantages in the NVH performance (NVH: noise, vibration, harshness) of the piston pump, but also disadvantages in relation to the maximum possible volume flow since after each pump stroke, the dynamic choke point closes again and the volume must flow through the integrated static choke point. This can lead to losses in the pressure build-up performance.
Publication DE 10 2011 079 876 A1 describes for example a piston pump for delivering fluids in a hydraulic vehicle brake system. The piston pump described comprises a cylinder, a piston mounted moveably in the cylinder, and a pressure chamber arranged between an inlet valve and an exhaust valve. The pressure chamber is closed by a cover. Downstream of the outlet valve in the fluid flow, a choke element which is configured as a spring-elastic disk is provided for choking the fluid flow. The spring-elastic disk is placed in the cover, wherein centering means are present in the cover which cause a pre-centering of the choke element in the cover. The piston pump described comprises a first choke point with a passage which is cleared independently of a differential pressure and has a defined constant flow cross section, and a second choke point with a passage which is cleared depending on a differential pressure and has a dynamic flow cross section depending on the differential pressure.